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# Copyright 2018 Kornia Team
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
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#     http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
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from typing import Dict, Optional, Tuple, Union

import torch

from kornia.augmentation.random_generator.base import RandomGeneratorBase, UniformDistribution
from kornia.augmentation.utils import _adapted_rsampling, _singular_range_check, _tuple_range_reader
from kornia.core.utils import _extract_device_dtype


class AffineGenerator3D(RandomGeneratorBase):
    r"""Get parameters for ```3d affine``` transformation random affine transform.

    Args:
        degrees: Range of yaw (x-axis), pitch (y-axis), roll (z-axis) to select from.
            If degrees is a number, then yaw, pitch, roll will be generated from the range of (-degrees, +degrees).
            If degrees is a tuple of (min, max), then yaw, pitch, roll will be generated from the range of (min, max).
            If degrees is a list of floats [a, b, c], then yaw, pitch, roll will be generated from (-a, a), (-b, b)
            and (-c, c).
            If degrees is a list of tuple ((a, b), (m, n), (x, y)), then yaw, pitch, roll will be generated from
            (a, b), (m, n) and (x, y).
            Set to 0 to deactivate rotations.
        translate: tuple of maximum absolute fraction for horizontal, vertical and
            depthical translations (dx,dy,dz). For example translate=(a, b, c), then
            horizontal shift will be randomly sampled in the range -img_width * a < dx < img_width * a
            vertical shift will be randomly sampled in the range -img_height * b < dy < img_height * b.
            depthical shift will be randomly sampled in the range -img_depth * c < dz < img_depth * c.
            Will not translate by default.
        scale: scaling factor interval.
            If (a, b) represents isotropic scaling, the scale is randomly sampled from the range a <= scale <= b.
            If ((a, b), (c, d), (e, f)), the scale is randomly sampled from the range a <= scale_x <= b,
            c <= scale_y <= d, e <= scale_z <= f. Will keep original scale by default.
        shears: Range of degrees to select from.
            If shear is a number, a shear to the 6 facets in the range (-shear, +shear) will be applied.
            If shear is a tuple of 2 values, a shear to the 6 facets in the range (shear[0], shear[1]) will be applied.
            If shear is a tuple of 6 values, a shear to the i-th facet in the range (-shear[i], shear[i])
            will be applied.
            If shear is a tuple of 6 tuples, a shear to the i-th facet in the range (-shear[i, 0], shear[i, 1])
            will be applied.

    Returns:
        A dict of parameters to be passed for transformation.
            - translations (torch.Tensor): element-wise translations with a shape of (B, 3).
            - center (torch.Tensor): element-wise center with a shape of (B, 3).
            - scale (torch.Tensor): element-wise scales with a shape of (B, 3).
            - angle (torch.Tensor): element-wise rotation angles with a shape of (B, 3).
            - sxy (torch.Tensor): element-wise x-y-facet shears with a shape of (B,).
            - sxz (torch.Tensor): element-wise x-z-facet shears with a shape of (B,).
            - syx (torch.Tensor): element-wise y-x-facet shears with a shape of (B,).
            - syz (torch.Tensor): element-wise y-z-facet shears with a shape of (B,).
            - szx (torch.Tensor): element-wise z-x-facet shears with a shape of (B,).
            - szy (torch.Tensor): element-wise z-y-facet shears with a shape of (B,).

    Note:
        The generated random numbers are not reproducible across different devices and dtypes. By default,
        the parameters will be generated on CPU in float32. This can be changed by calling
        ``self.set_rng_device_and_dtype(device="cuda", dtype=torch.float64)``.

    """

    def __init__(
        self,
        degrees: Union[
            torch.Tensor,
            float,
            Tuple[float, float],
            Tuple[float, float, float],
            Tuple[Tuple[float, float], Tuple[float, float], Tuple[float, float]],
        ],
        translate: Optional[Union[torch.Tensor, Tuple[float, float, float]]] = None,
        scale: Optional[
            Union[
                torch.Tensor, Tuple[float, float], Tuple[Tuple[float, float], Tuple[float, float], Tuple[float, float]]
            ]
        ] = None,
        shears: Union[
            None,
            torch.Tensor,
            float,
            Tuple[float, float],
            Tuple[float, float, float, float, float, float],
            Tuple[
                Tuple[float, float],
                Tuple[float, float],
                Tuple[float, float],
                Tuple[float, float],
                Tuple[float, float],
                Tuple[float, float],
            ],
        ] = None,
    ) -> None:
        super().__init__()
        self.degrees = degrees
        self.shears = shears
        self.translate = translate
        self.scale = scale

    def __repr__(self) -> str:
        repr = f"degrees={self.degrees}, shears={self.shears}, translate={self.translate}, scale={self.scale}"
        return repr

    def make_samplers(self, device: torch.device, dtype: torch.dtype) -> None:
        degrees = _tuple_range_reader(self.degrees, 3, device, dtype)
        shear: Optional[torch.Tensor] = None
        if self.shears is not None:
            shear = _tuple_range_reader(self.shears, 6, device, dtype)
            self.sxy_sampler = UniformDistribution(shear[0, 0], shear[0, 1], validate_args=False)
            self.sxz_sampler = UniformDistribution(shear[1, 0], shear[1, 1], validate_args=False)
            self.syx_sampler = UniformDistribution(shear[2, 0], shear[2, 1], validate_args=False)
            self.syz_sampler = UniformDistribution(shear[3, 0], shear[3, 1], validate_args=False)
            self.szx_sampler = UniformDistribution(shear[4, 0], shear[4, 1], validate_args=False)
            self.szy_sampler = UniformDistribution(shear[5, 0], shear[5, 1], validate_args=False)

        # check translation range
        self._translate: Optional[torch.Tensor] = None
        if self.translate is not None:
            self._translate = torch.as_tensor(self.translate, device=device, dtype=dtype)
            _singular_range_check(self._translate, "translate", bounds=(0, 1), mode="3d")

        # check scale range
        self._scale: Optional[torch.Tensor] = None
        if self.scale is not None:
            _scale = torch.as_tensor(self.scale, device=device, dtype=dtype)
            if _scale.shape == torch.Size([2]):
                self._scale = _scale.unsqueeze(0).repeat(3, 1)
            elif _scale.shape != torch.Size([3, 2]):
                raise ValueError(f"'scale' shall be either shape (2) or (3, 2). Got {self.scale}.")
            else:
                self._scale = _scale
            _singular_range_check(self._scale[0], "scale-x", bounds=(0, float("inf")), mode="2d")
            _singular_range_check(self._scale[1], "scale-y", bounds=(0, float("inf")), mode="2d")
            _singular_range_check(self._scale[2], "scale-z", bounds=(0, float("inf")), mode="2d")
            self.scale_1_sampler = UniformDistribution(self._scale[0, 0], self._scale[0, 1], validate_args=False)
            self.scale_2_sampler = UniformDistribution(self._scale[1, 0], self._scale[1, 1], validate_args=False)
            self.scale_3_sampler = UniformDistribution(self._scale[2, 0], self._scale[2, 1], validate_args=False)

        self.yaw_sampler = UniformDistribution(degrees[0][0], degrees[0][1], validate_args=False)
        self.pitch_sampler = UniformDistribution(degrees[1][0], degrees[1][1], validate_args=False)
        self.roll_sampler = UniformDistribution(degrees[2][0], degrees[2][1], validate_args=False)

        self.uniform_sampler = UniformDistribution(
            torch.tensor(0, device=device, dtype=dtype),
            torch.tensor(1, device=device, dtype=dtype),
            validate_args=False,
        )

    def forward(self, batch_shape: Tuple[int, ...], same_on_batch: bool = False) -> Dict[str, torch.Tensor]:
        batch_size = batch_shape[0]
        depth = batch_shape[-3]
        height = batch_shape[-2]
        width = batch_shape[-1]

        if not (
            isinstance(depth, int)
            and depth > 0
            and isinstance(height, int)
            and height > 0
            and isinstance(width, int)
            and width > 0
        ):
            raise AssertionError(f"'depth', 'height' and 'width' must be integers. Got {depth}, {height}, {width}.")

        _device, _dtype = _extract_device_dtype([self.degrees, self.translate, self.scale, self.shears])

        # degrees = degrees.to(device=device, dtype=dtype)
        yaw = _adapted_rsampling((batch_size,), self.yaw_sampler, same_on_batch)
        pitch = _adapted_rsampling((batch_size,), self.pitch_sampler, same_on_batch)
        roll = _adapted_rsampling((batch_size,), self.roll_sampler, same_on_batch)
        angles = torch.stack([yaw, pitch, roll], dim=1)

        # compute tensor ranges
        if self._scale is not None:
            scale = torch.stack(
                [
                    _adapted_rsampling((batch_size,), self.scale_1_sampler, same_on_batch),
                    _adapted_rsampling((batch_size,), self.scale_2_sampler, same_on_batch),
                    _adapted_rsampling((batch_size,), self.scale_3_sampler, same_on_batch),
                ],
                dim=1,
            )
        else:
            scale = torch.ones(batch_size, device=_device, dtype=_dtype).reshape(batch_size, 1).repeat(1, 3)

        if self._translate is not None:
            max_dx: torch.Tensor = self._translate[0] * width
            max_dy: torch.Tensor = self._translate[1] * height
            max_dz: torch.Tensor = self._translate[2] * depth
            # translations should be in x,y,z
            translations = torch.stack(
                [
                    (_adapted_rsampling((batch_size,), self.uniform_sampler, same_on_batch) - 0.5) * max_dx * 2,
                    (_adapted_rsampling((batch_size,), self.uniform_sampler, same_on_batch) - 0.5) * max_dy * 2,
                    (_adapted_rsampling((batch_size,), self.uniform_sampler, same_on_batch) - 0.5) * max_dz * 2,
                ],
                dim=1,
            )
        else:
            translations = torch.zeros((batch_size, 3), device=_device, dtype=_dtype)

        # center should be in x,y,z
        center: torch.Tensor = torch.tensor([width, height, depth], device=_device, dtype=_dtype).view(1, 3) / 2.0 - 0.5
        center = center.expand(batch_size, -1)

        if self.shears is not None:
            sxy = _adapted_rsampling((batch_size,), self.sxy_sampler, same_on_batch)
            sxz = _adapted_rsampling((batch_size,), self.sxz_sampler, same_on_batch)
            syx = _adapted_rsampling((batch_size,), self.syx_sampler, same_on_batch)
            syz = _adapted_rsampling((batch_size,), self.syz_sampler, same_on_batch)
            szx = _adapted_rsampling((batch_size,), self.szx_sampler, same_on_batch)
            szy = _adapted_rsampling((batch_size,), self.szy_sampler, same_on_batch)
        else:
            sxy = sxz = syx = syz = szx = szy = torch.tensor([0] * batch_size, device=_device, dtype=_dtype)

        return {
            "translations": torch.as_tensor(translations, device=_device, dtype=_dtype),
            "center": torch.as_tensor(center, device=_device, dtype=_dtype),
            "scale": torch.as_tensor(scale, device=_device, dtype=_dtype),
            "angles": torch.as_tensor(angles, device=_device, dtype=_dtype),
            "sxy": torch.as_tensor(sxy, device=_device, dtype=_dtype),
            "sxz": torch.as_tensor(sxz, device=_device, dtype=_dtype),
            "syx": torch.as_tensor(syx, device=_device, dtype=_dtype),
            "syz": torch.as_tensor(syz, device=_device, dtype=_dtype),
            "szx": torch.as_tensor(szx, device=_device, dtype=_dtype),
            "szy": torch.as_tensor(szy, device=_device, dtype=_dtype),
        }
